package zcw.com.lib_leet_code;

import java.util.Arrays;

/**
 * Created by 朱城委 on 2021/11/25.<br><br>
 *
 * 中等：最小路径和
 */
public class Topic64 {

    public static void main(String[] args) {
        Topic64 instance = new Topic64();
        int[][] array;
        array = new int[][] {
                {4}
        };
        System.out.println(instance.minPathSum(array));


        array = new int[][] {
                {1, 3, 1},
                {1, 5, 1},
                {4, 2, 1}
        };
        System.out.println(instance.minPathSum(array));

        array = new int[][] {
                {1, 2, 3},
                {4, 5, 6}
        };
        System.out.println(instance.minPathSum(array));
    }

    public int minPathSum(int[][] grid) {
        int row = grid.length;
        int col = grid[0].length;
        int[] dp = new int[col];
        Arrays.fill(dp, Integer.MAX_VALUE);
        dp[0] = 0;

        for(int i = 0; i < row; i++) {
            dp[0] = dp[0] + grid[i][0];

            for(int j = 1; j < col; j++) {
                dp[j] = Math.min(dp[j - 1], dp[j]) + grid[i][j];
            }
        }

        return dp[col - 1];
    }

    public int minPathSum2(int[][] grid) {
        int row = grid.length;
        int col = grid[0].length;
        int[][] dp = new int[row][col];
        dp[0][0] = grid[0][0];

        for(int i = 1; i < row; i++) {
            dp[i][0] = dp[i - 1][0] + grid[i][0];

        }

        for(int i = 1; i < col; i++) {
            dp[0][i] = dp[0][i - 1] + grid[0][i];
        }

        for(int i = 1; i < row; i++) {
            for(int j = 1; j < col; j++) {
                dp[i][j] = Math.min(dp[i - 1][j], dp[i][j - 1]) + grid[i][j];
            }
        }

        return dp[row - 1][col - 1];
    }
}
